1. Field of the Invention
The present invention relates to an image processing method and an image processing device in which an image recorded on a photographic photosensitive material is read and image processing is carried out on the image data obtained by reading.
2. Description of the Related Art
Conventionally, digital laboratory systems have been proposed in which an image recorded on a photographic photosensitive material (hereinafter simply referred to as "photographic film") such as a photographic film is read photoelectrically, various types of image processing are carried out on the image data obtained by reading, laser light is modulated on the basis of the image-processed image data, a photosensitive material such as a color paper is scanned and exposed, and a finished print is formed.
In this digital laboratory system, images recorded on photographic films having different photographic film characteristics (exposure amount-color forming density characteristics) are read. In order to obtain a proper image corresponding to the characteristics of the photographic film and the device which outputs the image, various types of corrections must be carried out by effecting image processing. (Examples of correction are gray gradation balance correction for correcting the balance of the three colors of R, G, B of the gray gradation in a normal exposure region, and photographic film non-linearity correction for correcting the non-linear portion in an underexposure region or overexposure region in a photographic film characteristic).
In the conventional digital laboratory system, various methods are employed for correcting the photographic film characteristics and determining the proper image processing conditions. For example, there is a method of carrying out image processing in which image processing conditions are determined from image data of a single image. In another method of carrying out image processing, the photographic film characteristics are estimated from image data of a plurality of images recorded on a single photographic film, and the image processing conditions are determined. In yet another method of carrying out image processing, the photographic film characteristics are estimated from image data of a large number of images recorded on plural photographic films of the same film type, and the image processing conditions are determined.
However, in the above-described conventionally-proposed image processings, in the method of determining image processing conditions from image data of a single image, the image processing conditions are very dependent on the photographed scene, and there is the possibly that density failure or color failure will occur. Further, the method in which the image processing conditions are determined from image data of one film is more accurate since there is a larger number of data, but the image processing conditions are still dependent on the photographed scenes. In the method in which the image processing conditions are determined from image data of plural films of the same film type, the image processing conditions are not dependent on the photographed scenes since there is such a large amount of data. However, photographic films, which have different photographic film characteristics due to different periods of time having passed since manufacturing of the film or development of the film or due to differences in development caused by different developing conditions, are treated as having the same characteristics. Thus, correction cannot be carried out which reflects the differences between the respective photographic films. Further, even in a method in which the photographic film characteristics themselves are stored and used in correction, correction cannot be carried out which reflects the aforementioned differences due to development and differences due to the passage of time.
Further, when reprinting is to be carried out (e.g., when additional prints are to be printed), there is the possibility that processing will be carried out under image processing conditions which are different than those at the time the initial prints were formed (e.g., at the time of simultaneous printing). Thus, the finished images will greatly differ between the prints formed initially and the prints formed at the time of reprinting.